3 2in su's

[rjc157]

thinking of doing a conversion is anyone out there running 3 hd8 carbs and what they used as far a manifolds

 

[Patrick67BJ8]

thinking of doing a conversion is anyone out there running 3 hd8 carbs and what they used as far a manifolds

Contact Nick Freeman of Nical Engineering in the UK. He has the manifolds and can help you with the setup, etc.

 

[Genos2]

I'm going to put them on my '63 BJ7, still waiting in one manifold to be completed. I had my stock tri-power manifolds(spares) welded in and machined out to fit the HD8 carbs,also running hotter camthan stock. The 2 manifolds that are finished look great, can't even tell they were welded after glass beaded.

 

[dougie]

I use three 2" SU HD8's on my '57 100-6 MM vintage racer which are run through a Ruddspeed period hi-performance tri-carb racing manifold. Very happy with the results.

[img:center]https://
DSC09702 by dougescriva, on Flickr[/img]

 

[HealeyRick]

At the risk of being the skunk at the picnic ... what else are you planning on doing to your car? To take advantage of that extra fuel, you are probably going to want a hotter cam, improved head, exhaust and ignition. My BJ7 had a BJ8 cam and 3 2in SUs on original Healey manifolds and a bit of porting It was a former SCCA racer in the 60s and was great at WOT, but was probably getting a bit too much gas at lower speeds.

 

[dougie]

At the risk of being the skunk at the picnic ... what else are you planning on doing to your car? To take advantage of that extra fuel, you are probably going to want a hotter cam, improved head, exhaust and ignition. My BJ7 had a BJ8 cam and 3 2in SUs on original Healey manifolds and a bit of porting It was a former SCCA racer in the 60s and was great at WOT, but was probably getting a bit too much gas at lower speeds.

I fully agree with Rick and should have added, my motor has all the mods mentioned above....and then some.

 

[HealeyRick]

Here's an idea of what Hollywood Sport Cars went through to take advantage of triple HD8s back in the 60s: https://www.healey6.com/Technical/Dyno.pdf Unless you're planning on putting your car on track, 3 HD8s are likely to be overkill

 

[Cottontop]

is anyone out there running 3 hd8 carbs and what they used as far a manifolds

I am putting 4 of them on the 5 Liter Ford V8 in my Healey.

Can't speak to performance. I haven't tried to start it yet, but they look cool.

Tim

 

[dougie]

Here's an idea of what Hollywood Sport Cars went through to take advantage of triple HD8s back in the 60s: https://www.healey6.com/Technical/Dyno.pdf Unless you're planning on putting your car on track, 3 HD8s are likely to be overkill

For what it's worth, I followed Doane Spencer's engine building directions from this article on my second race engine and achieved nearly the same results as HSC. My cam grind was slightly different, so I had a better torque line.

 

[Wings]

I changed a bj8(43011) over to 3 2's
Did the same w/ manifolds as you
I did get an lot of gas at the bottom end this would flood the engine for a fraction of a second then catch up, i am told if you play with the needles this can improve . i did not care for this part of the change over
At speed it was noticeable I could tailgate newer porches with the old car good fun
When i rebuilt the car i went back to 2 carbs
my 2 cents

 

[DerekJ]

Dougie,

Im considering an upgrade to my Hillclimb car over winter, ready for next season.

Im running two 2 inch SUs with a DWR8 fast road cam and 10.5 compression. I'm thinking of going to the DWR rally cam and seeing what happens. If necessary I might add a third SU.

How does this compare to your set up? Any thoughts.

regards

 

[dougie]

Hello Derek -

My current cam is probably closer to the one you currently have (DWR8) which allows my car to still be "streetable". If you have a ported and flowed head, I would look and increasing your lift through the rocker ratio. I run 1.65:1 with 11.5 compression and with the slightly milder cam, the power comes on in a smooth linear fashion. Just my thoughts, I built my motor to suit my driving style.

 

[DerekJ]

Dougie,

I need mine to be streetable as well as I drive it to and from the events like they did in the 50s and 60s. A guy I compete with runs the rally cam and triple Webers and he drives the longest distances of anyone. Next week I intend to have a drive in his car. He says the cam is fine for road use but we'll see.